1. Field of the Invention
The present invention relates to an electronic circuit device and a manufacturing method of the same. For example, the present invention is suitably used in a transmitting and receiving apparatus of an electronic key system of an automobile and the like and a manufacturing method of the same.
2. Description of Related Art
A known electronic circuit device as a transmitting and receiving apparatus of an electronic key system used in an automobile and the like accommodates a circuit board mounted with electronic parts, a battery and the like in a case in the shape of a flat plate (as described in JP-A-2004-52471, for example).
Generally, the case of the transmitting and receiving apparatus is made of a resin material. The circuit board is sealed in the case by performing an insert molding process of the circuit board along the flat-plate-shaped case when the case is molded. In this type of known electronic circuit device, both faces of the circuit board are entirely covered by the resin material. During the molding process of the case, the circuit board is held in the air inside a cavity of a molding die of the case with a holding pin formed in the molding die. Thus, the holding pin inside the molding die is necessary, and a structure of the molding die is complicated. In this case, a trace of the holding pin remains in the case as a hole after the molding process, deteriorating appearance. Moreover, there is a possibility that the circuit board is deformed because pressure locally acts on the circuit board due to hardening temperature difference of the resin or the mounted electronic parts are damaged when the resin hardens inside the molding die.